BEST ANSWER:No, not silk, but a good quality fleece. They are super warm and comfy. And they wash well, always a concern with fleece. My only concern is that the elastic in the waistband tends to roll.

BEST ANSWER:No, not silk, but a good quality fleece. They are super warm and comfy. And they wash well, always a concern with fleece. My only concern is that the elastic in the waistband tends to roll.